During the process of maturation of nervous system, various morphological as well as biochemical changes take place. Therefore, whatever the insult given during this period, it may cause damage of the nervous system which is quite different from those caused in mature nervous system. Various neuropathological lesions observed in varieties of metabolic disorders are also the results of developmental defect caused by the deficiencies or disturbances of enzyme systems which are necessary for the development of the nervous system. Therefore, overall objective of the proposed work is to study the neuropathological lesions induced by varieties of chemical or physical stimuli during the development of nervous system. Particular attention will be paid to the possible abnormalities in myelination and neuronal differentiation caused by such stimuli.